<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div {
            width: 100px;
            height: 100px;
            border: 1px solid coral;
        }
        div:hover {
            /*margin: 20px 0 0 20px;*/
            /*把元素改成相对定位*/
            position: relative;
            /*相对定位移动元素通过left/right/top/bottom*/
            top:20px;
            left:20px;
        }
    </style>
</head>
<body>
<div>div1</div>
<div>div2</div>
<div>div3</div>
</body>
</html>